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• Asbestos consists of certain types of fibrous material made up of silicates
• Silica may be combined with:
– Magnesium
– Iron
– Calcium
– Aluminum
• Asbestos is of two types:
1. Serpentine or Chrysolite –
– Hydrated magnesium
– 90% of world’s asbestos production
2. Amphibole
– Contains little magnesium
– Fibers are straight and longer than chrysotile fibers
• Asbestos is used in the manufacture of:
– Asbestos cement
– Fire proof textiles
– Roof tiling
– Brake lining
– Gaskets etc.
• Asbestos enters the body by inhalation and fine dust may be deposited in the alveoli
• The fibers are insoluble
• The dust deposited in the lungs causes pulmonary fibrosis leading to:
– Respiratory insufficiency and death
– Carcinoma of bronchus
– Mesothelioma of the pleura or peritoneum (otherwise a rare form of cancer) and
– Cancer of the gastro intestinal tract
• The risk of bronchial cancer is reported to be high if occupational exposure is combined with cigarette smoking
• The fibrosis is
– Due to mechanical irritation
– Is peri-bronchial,
– Diffuse in character and
• Basal in location - This is in contrast to silicosis

• Chapter 1 - Dust: Definitions and Concepts; Hazard Prevention and Control in the Work Environment: Airborne Dust WHO/SDE/OEH/99.14 available at:, accessed on 16th Feb 2017
• Park’s Textbook of Preventive and Social Medicine

Types of Pneumoconiosis:






Farmer’s Lung:

Lecture on Pneumoconiosis: